1. Field of the Invention
The present invention relates to an apparatus for modifying a traveling position of a paper web in a paper web processing machine. More particularly, it relates to an apparatus for modifying a paper web traveling position, which is capable of automatically modifying a deviation of a web-mounted position in a paper web processing machine such as a rotary press based on a detected value from a position of a side edge of a paper web drawn out from a rolled web. Such the deviation may be caused when the web is mounted on a position and the position is deviated in the axial direction of the web or a width of the paper web relative to a processing section due to a slight difference in inner diameters of the core tube in the web.
2. Description of the Related Art
An apparatus for modifying a traveling position of a paper web is shown as “Side lay device” on page 103, lines 3-20 in “Newspaper Printing Handbook” (issued by (Foundation) Nippon Newspaper Association on Apr. 10, 1997). The device employs a photo-electronic detecting means to detect a side edge of a traveling paper web drawn out from a rolled web. When the side edge of the traveling paper web is not located on an originally expected position, it operates a traveling position modifying means to modify the side edge of the traveling sheet so that it can be located on the originally expected position.
Japanese Utility Model Publication No. 58-29087 shows an example of the apparatus for modifying the traveling position of the paper web, which employs a sheet edge detector. The sheet edge detector is equipped with two sets of reflective photo-electronic detectors corresponding to both sides of a tolerable deviation range (a range that can permit a deviation) within which the side edge of the traveling paper web should be located originally, for example, a range extending each 1 mm to the left and to the right from the reference position. The sheet edge detector is located at a part that corresponds to the tolerable deviation range on the outer circumference of a guide roller that guides the paper web traveling. The outer circumference of the guide roller is colored black to ensure the detection of the light reflected from the white paper web. Based on the detected state of the light reflected from the paper web using the two sets of reflective photo-electronic detectors, it is possible to determine if the traveling position of the paper web falls outside the tolerable deviation range. If the side edge of the traveling paper web falls outside the tolerable deviation range, the apparatus for modifying the traveling position of the paper web is operated to modify the side edge of the traveling paper web to fall inside the tolerable deviation range.
The apparatus for modifying the traveling position of the paper web shown in Japanese Utility Model Publication No. 58-29087 requires the sheet end detector, which is detection means, to be attached precisely to the originally expected position of the paper web end, during the traveling of the paper web, determined relative to the center of the processing section, when the sheet end detector, which is detection means, is attached to the paper web processing machine. Such the attachment is difficult, however, and it requires a considerable experience and skill. In addition, it finally requires a practical operation of the paper web processing machine to obtain an accurately adjusted position for attachment.
The sheet edge detector, which is detection means, is equipped with two sets of reflective photo-electronic detectors each for detecting respective sides of the tolerable deviation range. Therefore, it is difficult to set the tolerable deviation range narrower and also difficult to process when a required accuracy is high on a position to be processed in the sheet width.